The variable phenotypes of haemoglobin D in Sri Lankan patients

Abstract

INTRODUCTION: There are only few reports of the occurrence of the variant haemoglobin, haemoglobin D Punjab (β 121 Glu-Gln) in Sri Lanka and its clinical spectrum has not been well documented. MATERIALS AND METHODS: During the clinical study of patients attending the thalassaemia clinic at Teaching Hospital Kurunegala we identified several individuals with haemoglobin D, some of whom had co-inherited it with other haemoglobin disorders. They were diagnosed using High Performance Liquid Chromatography (Bio Rad, USA) and later confirmed by polymerase chain reaction. CLINICAL STUDIES: Family 1: (Hb D-p thalassaemia) Describes a family with two individuals with haemoglobin D- β thalassaemia. Both were mildly anaemic but had severe hypochromasia and microcytosis. They were otherwise well. Family 2: (Hb D- Hb S disease) The propositus was an eight year old girl who presented with several episodes of sickling crises. Parents were carriers for Hb S and Hb D. Family 3: (Hb D- Hb E disease) The propositus was an individual with Hb E- Hb D disease. She was clinically well and the only abnormality was severe hypochromasia and microcytosis. DISCUSSION: Hb D when co-inherited with Hb E or thalassaemia does not appear to cause clinically significant disease. The co-inheritance of Hb D with Hb S, however, results in severe disease leading to sickling crises. Even though Hb D commonly does not cause severe disease, knowledge of its occurrence is important as the hypochromasia and microcytosis associated with it may lead to unnecessary iron therapy.